Concordance Therapy and Medication Adherence Interventions to improve antidepressant adherence in primary care settings that are effective, low-cost and easily disseminated are needed. To examine the utility of such interventions, several considerations require attention. First, differences in individual patient beliefs may significantly influence antidepressant adherence and will likely require individualized attention. Adherence may differ depending on whether the medication is being used acutely or in continuation treatment. Moreover, the adherence intervention may need to differ depending on whether the patient is in acute or continuation treatment. In addition, medical comorbidity is common among depressed primary care patients, and depression may have an adverse impact on adherence to medical regimens. In fact, depressive symptoms have been linked to inadequate treatment adherence in several chronic diseases, including diabetes mellitus, coronary artery disease, asthma, and hypertension. We propose to evaluate the effectiveness of a single modality adherence intervention (Concordance Therapy), delivered by primary care nurses, in a racially diverse sample of primary care patients with unipolar depression and comorbid diabetes mellitus or hypertension. We will also evaluate whether improvement in adherence to antidepressant treatment is associated with improvement in adherence to oral medication regimen for diabetes or hypertension. The intervention will be uniquely targeted to address identified and specific barriers to adherence in acute depression treatment, as well as specific impediments to adherence during continuation depression treatment. Specifically we plan to: 1 evaluate the effectiveness of Concordance Therapy to improve antidepressant adherence in primary care patients with unipolar depression and comorbid diabetes mellitus, or hypertension; and 2) To evaluate the impact of changes in antidepressant adherence on participants' adherence to oral medication regimen for diabetes or hypertension.